Transcript Classification of Living Things

Classification of Living Things
A Little History
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The Earth is 4.6 billion years old and microbial life is thought
to have first appeared between 3.8 and 3.9 billion years ago.
In fact, 80% of Earth's history was exclusively microbial life.
Microbial life is still the dominant life form on Earth.
The National Science Foundation’s “Tree of Life” project
estimates that there could be anywhere from 5 million to 100
million species on the planet, but science has only identified
about 2 million.
“We’ve only touched the surface of understanding animal life,”
said entomologist Brian Fisher of the California Academy of
Sciences. “We’ve discovered just 10 percent of all living things
on this planet.”
Why do we classify things?
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Supermarket aisles
Libraries
Classes
Teams/sports
Members of a family
Roads
Cities
Money
What is classification?
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Classification: putting things into orderly groups
based on similar characteristics
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Taxonomy: the science of describing, naming, and
classifying organisms
Early classification
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Aristotle grouped everything into
simple groups such as animals or plants
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He then grouped animals according to if they had
blood or didn’t have blood, and if they had live young
or laid eggs, and so on…
Binomial Nomenclature
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Developed by Carolus
Linnaeus
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Swedish Biologist 1700’s
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Two-name system
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Genus and species named
using Latin or Greek words
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When Linnaeus developed his system of classification, there were only two
kingdoms, Plants and Animals. However, the use of the microscope led
to the discovery of new organisms and the identification of differences in
cells. A two-kingdom system was no longer useful.
Today the system of classification includes six kingdoms.
The Six Kingdoms:
Plants, Animals, Protists, Fungi, Archaebacteria, & Eubacteria.
How are organism placed into their kingdoms?
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Cell type, complex or simple
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Their ability to make food
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The number of cells in their body
Archaebacteria
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In 1983, scientists took samples from a spot
deep in the Pacific Ocean where hot gases and
molten rock boiled into the ocean from the
Earth’s interior. To their surprise they
discovered unicellular (one cell) organisms in
the samples. These organisms are today
classified in the kingdom, Archaebacteria.
Archaebacteria are found in extreme
environments such as hot boiling
waterand thermal vents under
conditions with no oxygen or highly acid
environments.
Finding Archaebacteria: The hot
springs of Yellowstone National Park, USA, were
among the first places Archaebacteria were
discovered. The biologists pictured above are
immersing microscope slides in the boiling pool
onto which some archaebacteria might be
captured for study.
Eubacteria
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Like archaebacteria, eubacteria are complex
and single celled. Most bacteria are in
theEUBACTERIA kingdom. They are the
kinds found everywhere and are the ones
people are most familiar with.
Eubacteria are classified in their own
kingdom because their chemical makeup is
different.
Most eubacteria are helpful. Some
produce vitamins and foods like
yogurt. However, these eubacteria,
Streptococci pictured above, can give you
strep throat!
One celled
No separate nucleus
Example: bacteria
Protist
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Protists
Slime molds and algae are protists.
Sometimes they are called the odds and ends kingdom
because its members are so different from one
another. Protists include all microscopic organisms
that are not bacteria, notanimals, not plants
and not fungi.
Most protists are unicellular. You may be wondering
why those protists are not classified in the
Archaebacteria or Eubacteria kingdoms.
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It is because, unlike bacteria, protists are complex cells.
These delicate looking diatoms are classified in the protist
kingdom.
Most one celled
Have nucleus and other cell structures
Examples: algae, amoeba
Fungus
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Fungi
Mushrooms, mold and mildew are all examples
of organisms in the kingdom fungi.
Most fungi are multicellular and consists of
many complex cells.
Fun Facts about Fungi
Some fungi taste great and others can kill you!
Fungi are organisms that biologists once confused
with plants, however, unlike plants, fungi
cannot make their own food. Most obtain
their food from parts of plants that are decaying in
the soil.
Many celled
Cannot move
Absorb nutrients from other organisms
Examples: mushrooms, yeast, molds
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Plant
You are probably quite familiar with the
members of this kingdom as it contains all
the plants that you have come to know flowering plants,mosses, and
ferns. Plants are all multicellular and
consist of complex cells.
With over 250,000 species, the plant
kingdom is the second largest
kingdom. Plant species range from
the tiny green mosses to giant trees.
In addition plants
are autotrophs,organisms that make
their own food.
Many-celled
Cannot move
Autotrophs (Use energy from the sun to make
sugars)
Animal
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Animals
The animal kingdom is the largest kingdom
with over 1 million known species.
Sumatran Tiger - Kingdom: Animalia,
Phylum, Chordata, Class Mammalia, Order
Carnivora, Family Felidae,
Genus Pathera, Species tigris
All animals consist of many complex cells.
They are also heterotrophs.
Members of the animal kingdom are found in the
most diverse environments in the world.
Many-celled
Most can move
Get energy by consuming other organisms
Examples: invertebrates, fish, birds, mammals
The modern system of classification has 8
levels:
 Domain
 Order
 Kingdom
 Family
 Phylum
 Genus
 Class
 Species
Helpful way to remember the 8 levels
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Dumb kids playing catch on freeways get squashed
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Or…make up your own…
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DKPCOFGS
Using the Classification System
Field guides help identify organisms.
-they highlight differences between similar organisms
(like trees)
Taxonomic Key (Dichotomous Key)
-paired statements that describe the physical
characteristics of different organisms
Rules used to write scientific names
Homo sapiens
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An organism’s genus is always written first; the
organism’s species is always written second
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The genus is Capitalized; the species is
written in lower case
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Scientific names of organisms are always
italicized or underlined
Modern Taxonomy
The Evidence used to classify into taxon groups
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1) Embryology (splits animal kingdom)
2) Chromosomes / DNA
3) Biochemistry
4) Physiology (structure/function)
5) Evolution
6) Behavior
Taxonomic Key
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1a Fruits occur singly ................................................. Go to 3
1b Fruits occur in clusters of two or more ................ Go to 2
2a Fruits are round ................................................... Grapes
2b Fruits are elongate ............................................... Bananas
3a Thick skin that separates easily from flesh .........Oranges
3b Thin skin that adheres to flesh .............................. Go to 4
4a More than one seed per fruit ............................ Apples
4b One seed per fruit ............................................ Go to 5
5a Skin covered with fuzz.................... Peaches
5b Skin smooth, without fuzz........................... Plums
What steps would you use to identify an apple?